A biomarker, or biological marker, generally refers to a measurable indicator of some biological state or condition. Certain biochemical components, such as enzymes, proteins, nucleic acids, lipids, etc., can be used as biomarkers for the presence of the biological entity or condition (e.g., virus, bacteria, damaged cell, etc.) that created the biomarkers. The detection of the biomarker component can be used to detect the presence of the producing entity. As an example, a proteolytic enzyme, also referred to as a protease, peptidase, or proteinase, is an enzyme that performs proteolysis, or protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain forming the protein. The presence of particular proteolytic enzymes can be indicators of particular conditions. As a specific example, the HIV-1 protease is a retroviral aspartyl protease, and has been recognized as an essential element in maturation of the infectious virus. Accordingly, HIV-1 protease has been an important target for drug therapy.
At present, the majority of the developed methods for HIV detection are based on the detection of the presence of antibodies that the patient's body makes against HIV, direct molecular recognition of HIV and its components such as specific nucleic acid sequences or antigens, or measurement of the activity of HIV-1 protease, many of which are often laborious and time-consuming, and/or require the use of labels or sophisticated instruments.
There is a continuing need for improved detection of common and/or infectious diseases or conditions.